Abstract

Listeria monocytogenes is a facultative intracellular pathogen, ubiquitous and aetiological agent of listeriosis. The main Way of acquisition is the consumption of contaminated food and can cause Serious medical conditions such as septicemia, meningitis and gastroenteritis, especially in children, immunocompromised individuals and :seniors and abortions in pregnant women. An increase in cases of listeriosis worldwide has been reported and it is estimated that its prevalence in developed countries is in the range of 2 to 15 cases per one million population. This microorganism is characterized for the transition from the environment into the eukaryotic cell. Several Virulence factors have been involved in the intracellular cycle that are regulated, pimarilly, by the PrfA protein; which in turn is regulated by different mechanisms operating at the transcriptional, translational and post-translational levels. Additionally, other regulatory mechanisms have been described as sigma factor, system VirR/S and antisense RNA, but PrfA. is the most important control mechanism and is required for the expression of essential Virulence factors for the intracellular cycle.